How many kilojoules are in a kilowatt-hour?

One kilowatt-hour (kWh) equals exactly 3,600 kilojoules (kJ). This follows from 1 kWh = 1,000 W × 3,600 s = 3,600,000 J = 3,600 kJ.

How do I convert kilowatt-hours to kilojoules?

Multiply the number of kilowatt-hours by 3,600. For example, 2.5 kWh × 3,600 = 9,000 kJ.

How do I convert kilojoules to kilowatt-hours?

Divide the number of kilojoules by 3,600. For example, 18,000 kJ ÷ 3,600 = 5 kWh.

Is the kWh to kJ conversion exact?

Yes. By SI definition, 1 kWh = 3,600 kJ exactly. No rounding or approximation is involved.

Why do food labels use kilojoules instead of kilowatt-hours?

Kilojoules are the SI unit for energy and are used in scientific and nutritional contexts. Kilowatt-hours are a practical unit for electrical energy consumption. Both measure the same physical quantity.

How many kJ is a typical home's daily electricity use?

Average US household uses about 30 kWh per day, which equals 108,000 kJ (108 MJ). A single kWh represents 3,600 kJ.

Kilowatt Hours to Kilojoules Converter

Convert kilowatt-hours to kilojoules (or kJ to kWh) instantly — 1 kWh = 3,600 kJ exactly.

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Kilowatt-hours (kWh)

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Reference Table

kWh	kJ

Key fact: 1 kWh = 3,600 kJ exactly. This follows from 1 kWh = 1,000 W × 3,600 s = 3,600,000 J = 3,600 kJ.

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Summary

Kilowatt-hours (kWh) are the practical energy unit used on electricity bills and battery specs. Kilojoules (kJ) appear on food nutrition labels and in thermodynamics. One kilowatt-hour equals exactly 3,600 kilojoules, because 1 kWh = 1,000 W × 3,600 s = 3,600,000 J = 3,600 kJ. To convert kWh to kJ, multiply by 3,600. To convert kJ to kWh, divide by 3,600. The conversion is exact — no approximation involved.

How it works

Select a direction: kWh to kJ, or kJ to kWh.
Enter your energy value in the input field.
The result appears instantly with the formula shown below.
Click Swap to reverse the direction without clearing your value.
Use the reference table to look up common conversions at a glance.

Use cases

Convert electricity bill kWh readings into kilojoules for scientific or nutritional comparisons.
Translate food energy labels (kJ) into kWh for electricity-equivalent estimates.
Estimate home battery capacity in kJ from a rated kWh figure.
Cross-check solar panel output expressed in kJ against kWh meter readings.
Verify energy unit conversions in physics or engineering homework.
Compare energy content of fuels given in kJ per liter against kWh equivalents.

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Last updated: 2026-06-19 · Reviewed by Nham Vu